154 



THE FRUIT 



the Clematis achene (Fig. 261), and the tufted pappus 

 in the case of the Dandelion (Fig. 263). The wing of 

 the Maple key does not avail to carry the seed very far 

 from the source, on the average, as may be seen if we 

 examine the neighborhood of a Maple tree when the seed- 

 lings are coming up in the spring. The seedlings are 

 very numerous near the parent, very few at a distance of 

 two or three times the height of the tree. But one can- 

 not fail to be struck with the successful planting of the 

 seeds. Although not originally covered by the soil, they 

 stand in multitudes, rooted and growing, in spots where 

 the grass was beaten down and matted before the fruits 

 fell. Though bulky, the keys find their way into the 

 grass through the action of the winds in driving the 

 wings this way and that, until the seed ends have been 



worked well toward the moist sur- 

 face of the soil. This example 

 illustrates the fact, of common 

 occurrence, that appendages of 

 the fruit may serve both in dis- 

 semination and in placing the seed 

 in the position most likely to 

 secure germination. 



341. In connection with this 

 subject, the mechanism of Ero- 

 dium (Fig. 279) for burying the 

 fruit may be mentioned. The 

 elongated extremity of the fruit 

 is hygroscopic ; that is, it absorbs 

 vapor of water rapidly in damp 

 weather, and exhales it in dry, 

 the changes being accompanied 

 by twistings and untwistings. 

 As the fruit naturally falls with its weightier or seed 

 end toward the earth, these hygroscopic movements, aided 

 by backward-pointing hairs, enable it to work its way 

 through grass or other impediments toward the soil, and 

 finally even partially to bury itself. 



279. Fruit of Erodium. On 

 the left a single carpel 

 in damp weather; at 

 the right, several car- 

 pels in the calyx, in dry 

 weather. 



